The EcoTarium is great. They have a ton of animals inside, and do regular, very educational presentations for all ages. Most if not all of their employees are very ecologically conscious, and do a lot of work helping the animals and environment around Worcester. Stop by and see some cute animals and maybe even learn how you can help out. There's a planetarium there, too, and even some nature trails (in Worcester, who would have thought!), and is just an all around wondrous place. Adults are $8, children and seniors are $6. Parking's free.